1. Field of the Invention
The present invention relates to processes for the preparation of furan compounds. More specifically, it relates to a process for the preparation of furan compounds, in which a carbonyl compound or an equivalent thereof is allowed to react with an unsaturated compound having a carbon-carbon double bond, or a precursor thereof. Such furan compounds are useful typically as raw materials for polymers, intermediates for the synthetic preparation of highly functional materials and fine chemicals such as dyestuffs, pharmaceutical preparations, and bioactive substances, and intermediate materials for other organic chemicals.
2. Description of the Related Art
Furan compounds have been prepared, for example, by a process in which a 1,4-dicarbonyl compound as a starting material is subjected to cyclization-dehydration in the presence of an acid catalyst (Chem., Lett., 1983, 1007). This process, however, uses a hardly-available raw material, is not a versatile technique, and is thereby not an industrially efficient process for producing furan compounds.